Method for spraying rotating radial surfaces



Dec. 2, 1952 w. M WILLIAM 2,620,284

METHQDv FOR SPRAYING ROTATING RADIAL SURFACES Origin-a1 Filed Jan. 24,1949 2 SHEETS SHEET l T I' WALLACE m/wva/ fff fi' HTTOIFNEYS Dec- Z,1952 w. M WILLIAM 2,620,284

METHOD FOR SERAYING ROTATING RADIAL SURFACES ori inal Filed Jan. 24,1949 2 SHEETS-SHEET 2 IN V EN TOR.

Wmmce Mac WILL/HM ATTORNEYS Patented Dec. 2, 1952 METHOD FOR SPRAYINGROTATING RADIAL SURFACES Wallace MacWilliam, Boonton, N. J., assignor toEclipse Air Brush 00., Newark, N. J., a corporation of New JerseyOriginal application January 24, 1949, Serial No. 72,411. Divided andthis application October 27, 1950, Serial No. 192,412

2 Claims.

This invention relates to the problem of uniformly spraying rotatingradial surfaces. For example, steel drum heads may be painted byrevolving the drum about its axis and using fixed paint spray gunspointing towards its opposite drum heads. But the peripheral portions ofthese rotating radial surfaces travel faster than their central portionsso the latter receive a greater amount of paint than the peripheralportions per unit of time. This results in a radially uneven coatingwhich is undesirable. The thus presented problem has not beensatisfactorily solved heretofore either by using multiple guns fixed ateach drum head or by using movable guns adapted to traverse the drumheads.

One object of the present invention is to spray rotating radial surfacesin a uniform manner. This application is a division from applicationSerial No. 72,411, filed January 24, 1949, on which Patent No. 2,613,635issued on October 14, 1952. This patent contains claims covering theapparatus disclosed herein.

The presently preferred form of the invention is illustrated by theaccompanying drawings as embodied in an automatic drum head spraypainting machine, the various figures being as follows:

Fig. 1 is a top view of a drive and countershaft assembly forming thetop portion of the machine, certain lower elements being eliminated inthe in terest of clarity;

Fig. 2 is a side view of the complete machine showing the drive andcountershaft assembly of Fig. l and its location, and all the otherparts therebelow and including in broken lines a steel drum with itsheads being spray painted;

Fig. 3 is an end view of Fig. 2;

Fig. 4 is a cross section of the drive and countershaft assembly takenfrom Fig. 2 as indicated by the line 4-4 and Fig. 5 is a fragmentaryview taken from the line 5-5 in Fig. 3 for the purpose of showing aspray angularity not adequately illustrated otherwise.

In these drawings the drum D is shown by broken lines. formed by fourrectangularly arranged wheels I which are generally shaped like railroadwheels so they provide inwardly tapered drum supporting surfaces 2having flanges 3 for engaging the drum ends and preventing axial drummotion.

The drum is horizontally cradled by these wheels I with the latterappropriately positioned by horizontally journaled shafts 4 of whichboth are rotatively powered by the sprocket wheel 5 connected by thesprocket chain 6 with the sprocket The machine provides a cradle I!wheel 1 on the shaft of an electric rotory motor M. Those wheels I whichare on the shafts are keyed thereto. Therefore, operation of the motorM, which is an electrical motor whose speed is capable of good control,serves to rotate the drum D about its axis with this axis relativelyfixed due to the form and arrangement of the wheels I which carry it.

Levers 8 are each fulcrumed on an axis parallel to and radially offsetfrom the rotary axis of the cradled drum D by being keyed to thehorizontal shafts 9 of right angle gear drives I0 having their verticalshafts II connected to the vertical shafts I2 of other generally similarright angle gear drives I3, by vertical shafts I I provided withuniversal joints I5. The drives I0 are elevated above the drum D when itis supported by the wheels I and the drives I3 are above the drive I0with the shafts I4 and the universal joints I5 permitting horizontalmovement of the drives I0 axially of the drum D. For this purpose thedrives I0 are slidably mounted on horizontal supports I6 and providedwith releasable fastenings IT for fixing the position of the drives I0and hence the levers 8 relative the drum heads. These horizontalsupports I6 may be supported by an adequate superstructure or suspendedfrom the shop ceiling, this applying also to the drives I3 and any otherelevated equipment. The particular arrangement used for this purpose isnot illustrated in the interest of avoiding confusion in the drawings.

The horizontal shafts of the right angle gear drives I3 areinterconnected by a countershaft I8 to which a lever I9 is keyed withits swinging end connected by a connecting rod 20 to a crank 2I keyed toa drive shaft 22 powered by an electric rotory motor 23 through areduction gear drive 24. With this arrangement, as the motor 23 slowlydrives the shaft 22 through the gear drive 24, the crank 2I rotatestherewith, and the connecting rod 20 oscillates the lever I9 tooscillate the shaft I8 and hence the levers 8 depending from thehorizontal shafts 9 of the right angle gear drives I0. The lower ends ofthe levers 8 are thus caused to traverse the heads of the cradled drumD, and these lower ends mount automatic fan spray guns 25. These gunsare of the type like a manual fan spray gun, excepting that they areoperated by a pilot plunger adapted to be remotely controlled by theadmission of pilot air pressure. It should also be understood that a fanspray is a relatively flat flaring spray ejected from a spray gun havinga spray head designed to so shape the spray.

The fan spray guns 25 are mounted by the ower ends of the levers 8 sothat the fan spray is ejected approximately in alignment with the levers8 in each instance. The levers 8 are shown as having lengthsapproximately equaling the drum diameter, and their mounting shafts 9are positioned high enough so that the lower ends of the fan spraysterminate about at the drum axis. The shafts 9 are positioned in radialalignment with the drum axis and are vertically thereabove and when thelevers 8 are swung in alignment with the drum axis and the axes of theshafts 9, the fan spray is oriented approximately radially respectingthe drum head in each instance. When the levers 8 are swung outwardly sothey are opposite the periphery of the drum or are close thereto the fanspray is oriented approximately tangentially respecting the drum head ineach instance. t positions in between the fan spray rotates so as toprovide transitional orientations between the radial and tangentialorientations at the inner and outer extremes of its swing in eachinstance. The spray guns 25 are each arranged to eject their fan spraystransversely towards the drum heads and in each instance at outwardlyinclined angles as shown by Fig. 5.

All of the right angle gear drives have 1 to 1 gear ratios and the upperdrive and countershaft assembly is organized so that when the crank 2|is aligned with the link 2!} the arms 8 are opposite the periphery ofthe drum heads and when the crank 2| and connecting rod are at rightangles the levers 8 are at the axes of the drum heads. The organizationis such that at this time the lever I9 is vertical. This lever I9oscillates with rotation of the crank 2| as it is driven by the motor23. Thus the arms 3 oscillate back and forth while completely traversingthe drum heads.

The illustrated machine is designed for full automatic operation, theautomatic spray guns having their pilot pressure connected with a pilotvalve 26 worked by a cam 21 on the shaft 22. There is also a limitswitch 28 worked by a cam 29 on the shaft 22. This limit switch 28 isconnected by an electric circuit to control the motor 23 so that uponinitial energization the crank 2| makes one complete rotation and thenstops until the circuit is energized again, with a manually operatedpush button used to initiate each cycle. The cam 27 is arranged so thatas the crank 2i starts to align with the connecting rod 28 while thelevers 8 are at their outer swinging extremes where the {an spray guns25 are pointing outwardly as shown by Fig. 5, pilot pres- L sure isadmitted to the guns 25 so that they start to eject their fan sprays,and this is continued until the levers 8 swing to positions where theyare opposite the central portions of the drum heads with the fan spraysextending radially from the 5 drum head axis, whereupon the pilotpressure is discontinued so the spray ceases.

In the above operation the drum D is, of course, rotating when the sprayguns are pointing towards the peripheral portions of its drum heads.These drum heads receive at this time the maximum amount of sprayperipherally for each revolution because of the tangential orientationsof the fan sprays. The arrangements should be such that as sprayingstarts the fan sprays are pointing at their outward inclinations so thattheir spray ends just reach into the chines of the drum, the outwardinclinations assuring that these chines are thoroughly sprayed.

As the crank 2| and link 20 begin to leave their aligned positions themechanical advantage is so great that there is time for the drum headsto turn at least twice so as to positively avoid an unsprayed portionbetween the ends of the fan sprays. There is no chance for the side ofthe drum to be sprayed because of the outward inclinations of the sprayguns, this being another important advantage of this angularity since itis frequently desired to paint the sides of the drum a different colorfrom its heads.

As the crank 21 continues to rotate and gradually approach rightangularity with the connecting rod 20, the traversing speeds of the arms8 correspondingly increase in accordance with the laws of mechanicsinvolved. Since the spray guns are rigidly fixed to the ends of the arms8 and the latter are swung about the axis formed by the shafts 9, thefan sprays gradually leave their tangential orientations and rotate, ineffect, about their own axes relative the drum heads and as they beginto approach their radial orientations they are swinging faster. The drumhead portions that are sprayed are, of course, moving slower since theyare closer and closer the drum axis. By proper relation of these variouseffects the drum heads may be sprayed in a completely uniform manner.

The rotating speed of the drum must be correlated to the swinging speedsof the levers 8 to prevent the fan sprays from forming spiral patternson the drum heads. This is particularly important while the arms areopposite the peripheral portions of the drum heads with the fan spraysoriented tangentially respecting the drum heads.

Knowing the fan sprays dimensions, the dimensions of the various leversand of the crank 21, and the latters rotating speed, it is possible tomathematically compute the proper drum r0- tating speed required. Withthe motor 1 capable of good speed control it is also possible to vary itas required to visually produce the desired uniform results.

In the case of the specific example illustrated, the drum heads are 23/4 inches in idameter and the motor 1 is set to rotate the drum at R. P.M. The fan spray pattern is 6 inches long and /2 inch wide or thick, andthe levers 8 are about 24 inches long. The right angle gear drives allhave 1 to 1 gear ratios, and the crank 2| and lever 19 are dimensionedas required to fully swing the levers 3 from the drum heads periphery tothe center while the crank 2| turns from alignment with the connectingrod 26 to the right angular association there with. With thisarrangement a crank speed of 8.24 R. P. M. produces the desired results.The fan sprays are set to automatically start as the crank 2| reachesdead center and before it can break its toggle linkage with the lever [9the drum heads have time to turn enough to avoid uncoated peripheralportions. The cam 21 is set to cut oif the pilot pressure, to theautomatic spray gun, just as the fan sprays become aligned with the drumheads axis. This means that the levers 8 swing a little beyond the axisof the drum, it being remembered that the fan spray guns are set toeject their fan sprays at the outward inclinations required to paint thechines and avoid painting of the drum sides.

Some difficulty may be experienced in properly spray painting the bunghole, so the machine is provided with a fixed automatic spray gun 30which may eject an ordinary round spray in alignment with the bung hole,it may be used when required for this special purpose.

It is to be noted that a manual fan spray gun may be manipulated toimitate the motions obtained by this machine. This involves a methodphase that is believed novel. Although apparently more complicated, thevarious orientations and traverse of the fan spray might be imitatedmore or less by using a true linear traverse with rotation of the fanspray effected by cam action or the like. Various other ways may besuggested by those skilled in the art for doing substantially the samething in substantially the same manner as disclosed by the descriptionof this specific form. of the present invention.

The fan spray has been described as oriented approximately tangentiallyrespecting the drum head or disk. With the lever 8 arranged so that whenit is at the drum heads center it is truly radial therewith, asillustrated, better results may be obtained by orienting the fan spray,by arranging the gun, so the spray is at a angle with the lever. It maybe given an angle as large as 45 with the lever and still provide someor the described advantages. But the fan spray should in each instancebe substantially or approximately tangential to the rotating disk beingcoated.

I claim:

1. A method for substantially uniformly spraying an article having asubstantially flat circuiar surface, said method comprising rotatingsaid article so as to rotate said surface about its axis, ejecting a fanspray transversely against said surface, moving said spray in agenerally radial manner respecting said surface to traverse the radiusthereof, and, during said moving, orienting said spray so that it issubstantially tangential to the rotation of said surface while at theperiphery of said surface and so that it is substantially radial to saidsurface while at the center of said surface and so that said sprayprogressively rotates about its own axis from one of said orientationsto the other thereof while moving from one of said positions to theother of said posiitons.

2. A method for substantially uniformly spraying an article having asubstantially flat circular surface, said method comprising rotatingsaid article so as to rotate said surface about its axis, ejecting a fanspray transversely against said surface, moving said spray in agenerally radial manner respecting said surface to traverse the radiusthereof, and, during said moving, orienting said spray so that it issubstantially tangential to the rotation of said surface while at theperiphery of said surface and so that it is substantially radial to saidsurface while at the center of said surface and so that said sprayprogressively rotates about its own axis from one of said orientationsto the other thereof while moving from one of said positions to theother of said positions, the speed of said moving and the length andwidth of said fan spray being correlated respecting the rotating speedof said surface to effect a substantially uniform spraying of saidsurface throughout its extent.

WALLACE MACWILLIAM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,831,535 Juers Nov. 10, 19311,835,402 Juers Dec. 8, 1931 1,956,220 Johnson et al Apr. 24, 1934

1. A METHOD FOR SUBSTANTIALLY UNIFORMLY SPRAYING AN ARTICLE HAVING ASUBSTANTIALLY FLAT CIRCULAR SURFACE, SAID METHOD COMPRISING ROTATINGSAID ARTICLE SO AS TO ROTATE SAID SURFACE ABOUT ITS AXIS, EJECTING A FANSPRAY TRANSVERSELY SAID SURFACE, MOVING SAID SPRAY IN A GENERALLY RADIALMANNER RESPECTING SAID SURFACE TO TRAVERSE THE RADIUS THEREOF, AND,DURING SAID MOVING ORIENTING SAID SPRAY SO THAT IT IS SUBSTANTIALLYTANGENITAL TO THE ROTATION OF SAID SURFACE WHILE AT THE PERIPHERY OFSAID SURFACE AND SO THAT IT IS SUBSTANTIALLY RADIAL TO SAID SURFACEWHILE AT THE CENTER OF SAID SURFACE AND SO THAT SAID SPRAY